If Aaron Rodgers were drafted by the Raiders he'd probably be out of the league by now. Those 3 years on the bench behind Favre were invaluable.
Or imagine the 2nd rounder Montana being drafted by the Bucs and having no Rice or Craig or Walsh.
Or imagine Brady going to the Lions. He probably ends up their starter but no way does he have the success he's having now with Belicheck.
Thats what helps Manning's case when you're talking about the Goat IMO. Same with Elway. It just seems like those guys created the system and culture and wernt brought up in it.